<form class="form-inline" ng-submit="login()">
  <div class="form-group">
    <label class="sr-only">邮箱</label>
    <input type="email" required class="form-control" ng-model="email" placeholder="请输入邮箱号" />
  </div>
  <button type="submit" class="btn btn-primary btn-enter">Enter</button>
</form>
